FIG. 1 shows the structure of a conventional display substrate having a base substrate 11, a black matrix 12, color filters, and a protective layer 14. Typically, the color filters correspond to pixel regions, the black matrix 12 corresponds to a boundary region between adjacent pixel regions. As shown in FIG. 1, the color filters are spaced apart by the black matrix 12. FIG. 1 illustrates the structure of a display substrate having a red color filter and a blue color filter, which form a gap above the black matrix 12. The protective layer 14 is formed over the color filters and the black matrix 12. The gap between two adjacent color filter results in a recess having a depth ΔH in the protective layer 14 at a region above the black matrix 12. Typically, the depth ΔH is in the range of about 0.5 μm to about 1.0 μm. In a conventional display substrate, a spacer is disposed within the recess.